[Bug 207208] ping has a problem with fragmented replies

[Maxim Konovalov]

Hello,

> # netstat -sp ip
> ip:
>         0 fragments received
{...]
>         22 datagrams that can't be fragmented
>
[...]

The above looks suspicious.  Here is what it should be:

# netstat -sz >/dev/null
# netstat -sp ip | grep frag
        0 fragments received
        0 fragments dropped (dup or out of space)
        0 fragments dropped after timeout
        0 output datagrams fragmented
        0 fragments created
        0 datagrams that can't be fragmented
# ping -qc 1 -s 2500 80.113.23.178
PING 80.113.23.178 (80.113.23.178): 2500 data bytes

--- 80.113.23.178 ping statistics ---
1 packets transmitted, 1 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 59.983/59.983/59.983/0.000 ms
# netstat -sp ip | grep frag
        2 fragments received
        0 fragments dropped (dup or out of space)
        0 fragments dropped after timeout
        1 output datagram fragmented
        2 fragments created
        0 datagrams that can't be fragmented

To test ip fragmentation withoug NAT you can simple run

ping -s 32000 -c1 127.0.0.1

and check stats above.

I still think that your NAT is culprit.

-- 
Maxim Konovalov